1. **State the problem:**
We have 5000 tickets sold at 1 each for a raffle. Prizes are:
- 1 prize of 700
- 3 prizes of 300
- 5 prizes of 10
- 20 prizes of 5
We want to find the expected value $E(X)$ of the amount won if you buy 1 ticket.
2. **Formula for expected value:**
$$E(X) = \sum (\text{value of prize} \times \text{probability of winning that prize})$$
3. **Calculate probabilities:**
- Probability of winning 700: $\frac{1}{5000}$
- Probability of winning 300: $\frac{3}{5000}$
- Probability of winning 10: $\frac{5}{5000}$
- Probability of winning 5: $\frac{20}{5000}$
- Probability of winning nothing: $1 - \frac{1+3+5+20}{5000} = 1 - \frac{29}{5000} = \frac{4971}{5000}$
4. **Calculate expected value:**
$$E(X) = 700 \times \frac{1}{5000} + 300 \times \frac{3}{5000} + 10 \times \frac{5}{5000} + 5 \times \frac{20}{5000} + 0 \times \frac{4971}{5000}$$
5. **Simplify each term:**
$$= \frac{700}{5000} + \frac{900}{5000} + \frac{50}{5000} + \frac{100}{5000} + 0$$
6. **Sum the numerators:**
$$= \frac{700 + 900 + 50 + 100}{5000} = \frac{1750}{5000}$$
7. **Simplify the fraction:**
$$= \frac{\cancel{1750}^{350}}{\cancel{5000}^{1000}} = \frac{350}{1000} = 0.35$$
**Final answer:**
$$E(X) = 0.35$$
So the expected value of the raffle ticket is 0.35 dollars, meaning on average you expect to win 35 cents per ticket bought.
Raffle Expected Value 1D343C
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